Apparatus for casting dental inlays.



c. L. KEMBRY. APPARATUS FOR CASTING DENTAL INLAYS.

APPLICATION FILED MAR. 27,1908.

Patented Mar. 8, 1910.

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Application flied March 27, 1808. Serial No. 423.680:

To all whom it may concern:

Be it known that 1, CHARLES L. KEMERY, a resident of Pittsbur in the count of Allegheny and State of Pennsylvania, have invented a new and useful Tm rovement in Apparatus for Casting Dental nla s;',and][ do ereby declare the following to e a full, clear, and exact description thereof.-

This invention relates to ap aratus for casting dental inlays, crowns, ridges and plates. r

The purpose of the invention is to pro-' vide a device of this character which is neat and compact, which can be readily'and, easily used, which can be adapted to the usual apparatus and equi ment of a dentists office, and whichwil cause the metal to fill out in all of. the sharp angles and crevices of the mold.

The invention comprises a rotatable furnace of the -,character hereinafter described and clairnbd, 1

V In the faccom anying drawings Figure 1 is a side view of. a dental lathe showing my furnace applied thereto; Fig. 2 is a vertical section through the'furnace on an enlarged scale; Fig. 3 1s'a transversesection through the lower part of the furnace and Fig. 4 is a view showing the means or connecting the flask to the furnace proper.

My improved furnace comprises a suitable casing 1 inclosing a chamber 2 which is lined with some suitable fire resisting material 3. The furnace chamber has an opening 4 on one side. In the bottom of the chamber is a crucible 5 of carbon, lumbago, or other material which is a con actor of electricity. This crucible rests u n the metallic bottom tiwhich is. connecte to the. casing 1 by studs 7 and bearing or clamping plates 8, nuts 9 being used to fasten the parts together. The metallic bottom 6 is suitabl -1nsulated from the casing 1 such sulating material.

as by s eets 10 of mica, or other suitable in- ]Prqectmg downwardly from the bottom 6 is a? ring 12, which on two diametrically opposite oints is provided with bayonet slots. 14: or receiving'pins 15 on the cup shaped flask 16. This provides a connection between-the flask and the furnace by means of which the flask can'be readily disconnected. The flask 6 .will have formed therein a mold 17 of any suitable investment material, by means of a wax or other. at-

tern, as is now the practice. The top 0 the mold is preferably formed concave, as shown, at 18, and communicates with themold cav- 1ty 19 through an opening or gate 20. The

' crucible 5 and bottom 6 are provided with openings 21 in line "with the gate 20 of the mold. y I g The metal to form'the inlay, such as gold, is placed in the crucible 5 and is melted therein, preferably by an electric current.

To this end one terminal of the circuit is connected to the crucible, such as by connecting a binding post 22 to one of the studs 7.. This connection will be made in any suitable manner so as to become readily disconnected when the furnace starts to revolve. The other terminal is formed b an electrode 23 carried on a handle 24 and aving preferably the negative w ire' 25 0on nected thereto. in the circuit is placed a1'7 5 suitable adjustable resistance 26 so that the current can be regulated at will. en the circuit is closed an arc is formed between the crucible and the electrode 23, which are melts the metal contained in the quickl crucib e. The molten metal liesin a globule over the opening 21 in the bottom of the crucible ready to be thrown by centrifugal force as soon as the furnace is started to revolve.

Gold and other metals generally used for dental purposes have a tendencyto form into beads or take a lobular form so that they do not fill wolf out into the sharp angles of the mold cavity. In order that r the metal may fill all the recesses of themold cavity, my furnace is designed toforce the metal into the mold by centrifugal force. To that end the furnace casingl has connected'thereto an arm 28 provided with e fi ed socket 29 for attachment to the a ta spin e 30 of an ordinary dentists lathe, or other rotating mechanism. In use, as'soon as the gold is melted tor starts the lathe, trolled h the foot, or electric switc setting the spin le 30 into rotation and thereby rotating the furnace on a horizontal axis. Since the axisof rotation is-near the top of the furnace, this causes the crucible and 1025 mold to traverse an orbital path around the axis and the centrifugalforce acting on the molten metal positively throws the same through theiopenings 21 and 20 and into the causing the metal to flow out 110 mold cavity,

in all of the crevices and she angles ofthe "bavity and forming, an ay which achi the arc, the operaw ich usuall is 'con curately conforms to the pattern and to the cavity in which itis tobe laced.

The apparatus describe is compact and 1 neat in appearance, can be applied to the ordinary appliances found in a dentists of- ,fice, can be-readlly operated, and insures the formatlon of' inlays, crowns, and bridges having sharp contoursconforming to the mold.

- It will be observed that in theuse of the device the gold or other metal is placed inthe furnace when the same is 1n an upright position, so that the-metal is held by gravity in the crucible and tends, when melted, to

v flow down through the hole in the bottom of v molten metal cannot spill or become wasted.

What I claim is: 1. Apparatus for casting dental inlays,

crowns and bridges, comprising a furnace 6.0 extending radially with reference to the axis constructed for rotation on a horizontal axis, an electric terminal connected to the furnace hearth, an electrode forming the other terminal of the circuit, and a mold carrier connected to the furnace and having a communication with the furnace hearth radial to the axis of rotation, whereby the centrifugal action due to the rotation of the furnace forces the molten metal into the mold.

2. Apparatus for casting dental -inlays, crowns and bridges, comprising a furnace constructed for rotation on a horizontal axis, a crucible resting in the bottom of the furnace and provided with 'a hole through its bottom; a terminal connected to said crucible, an electrode forming the other ter; minal of the circuit, and a mold carrier connected to the furnace and arranged to have the mold gate in line with the hole in the bottom of the crucible and radial to the axis of rotation, whereby the centrifugal action forces the molten metal into the mold. 3. Apparatus for casting dental inlays, crowns and bridges, comprising a furnace constructed for rotation on a horizontal axis, a crucible in the bottom of said f-urnace .and provided with ahole through its bottom of such a size that the molten metal will not pass through until acted uponby the centrifugal. force caused by the rotation of the furnace, an electric terminal con- -'nected to said crucible, an electrode forming the other terminal ofthe circuit, a flask connected to the bottom of the furnace and .of rotation .and arranged to have the mold minal of the circuit, and a flask detachably connected to the bottom of said furnace and arranged to have the mold gate in radial relation to the opening in the bottom of the furnace.

5. Apparatus for casting dental inlays, crowns and bridges, comprising a furnace constructed for rotation on a horizontal axis, a crucible in the bottom of said furnace and insulated therefrom and provided with a hole through its bottom, a terminal connected to said crucible, an electrode forming the other terminal of the circuit, and a mold carrier connected to the bottom of the furnace and presentin the mold gate in radial relation to the hole 111 said cruclble,

so that the centrifugal force created by the revolving furnace causes the molten metal in the bottom of the crucible to be forced radially out into the mold and form a perfect cast.

6. Apparatus for casting dental inlays, crowns andb-ridges, comprising a furnace constructed for rotation on a horizontal axis and having an opening through its bottom, an electric terminal connected to said furnace bottom, an electrode forming the other terminal of the circuit, and a flask connected to the bottom of the furnace by a bayonet joint connect-ion and presenting the mold gate in radial relation to the hole in the bottom of the furnace.

7. Apparatus for casting dental inlays, crowns and bridges; comprising a furnace provided above its bottom with means for attachment to a horizontal shaft, a hole through the bottom of said furnace, and a flask connected to the bottom of the furnace and extending radially with reference to the CHARLES L. KEMERY.

Witnesses:

M. D. VOGEL, Ron'r. D. Torrnrr. 

